JP2810857B2 - Communication data stream conversion method and system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data transmission, and more particularly to encoding binary and non-data signals transmitted over a serial data link having a desired data pattern with low complexity and high efficiency. A new method of decryption and decryption.

[0002]

BACKGROUND OF THE INVENTION In digital data transmission systems, binary data representing a particular form of information is encoded in digital form and transmitted over a network. For example, pulse code modulation (PC) widely used in the U.S. telephone network
In M) systems, the analog audio signal is quantized into a number of discrete levels, and codes are also used to specify each level at each sample time. As a result, the transmitted audio signal is represented by a string of binary data, ie, "0" or "1". In standard data transmission settings, such as in a local area network (LAN), binary string data from one node in the LAN is transmitted to another node connected to the LAN. The characteristics of the transmitted data string vary according to the prescribed protocol with which it conforms.

The choice of the protocol used depends on a number of factors, such as the type of modulation and demodulation used (in telecommunications), bandwidth limitations, receiver complexity, and the like. In any case, the binary data must be represented such that it has the appropriate electrical characteristics for transmission over a transmission medium such as twisted pair copper wire. For example, it is advantageous that the coding method used is self-clocking, ie the clock frequency is easily found from the pulse code. The receiving side becomes easier to synchronize if the transmission data is encoded by a method having a self-clocking function.

Also, the average value of a transmitted binary data string is 0 volts (ie, the data string is symmetric, low or zero in "non-evenness (disorder).
parity), ie the polarity of the bits of the data string is balanced. An example of a string having an average value of 0 volts is when the accumulated positive voltage is equal to the accumulated negative voltage. If there is a high degree of non-evenness (ie, there are many more bits of one polarity than bits of the other polarity), the components of the high-pass circuit in the transmission path and the low-frequency energy in the long bit sequence The interaction filters out the low frequency energy of the bit string, causing data loss.

[0005] These problems (ie, high levels of non-evenness, etc.) are particularly evident when data is transmitted in high-speed data transmission systems (eg, LAN or ATM networks), in which the transmitted data is transmitted. Digital binary information streams have few characteristics that make them suitable for useable and cost-effective transmission links. Typically, the information transmitted in such an environment is very random or very repetitive in nature.
These characteristics (high randomness or repetition) are unsuitable for high-speed transmission.

[0006] Random data, such as compressed and encrypted data, has the property that any bit sequence in the random bit stream can occur as well as any other sequence. For example,
A string of ten 1s in a row is a 10-bit 102
It is expected that, on average, one occurrence occurs for four (2 ¹⁰ ) types of strings.

The problem is that long bit strings without transitions adversely affect data transmission performance. This occurs for two reasons. One is that the clock recovery circuit operates poorly without bit transitions. Another reason is that a high degree of non-parallelism, as described above, causes high-pass circuit components in the transmission
This causes an interaction with the low frequency energy in the sequence.

[0008] Repetitive data or data comprising a string of repetitive bit sequences concentrates the frequency spectrum of the transmitted signal into several frequency ranges, or even worse, into a single frequency range. A string can occur when data representing a screen display is transmitted over a network and one bit string represents a particular background color of the screen). This state is
During the design, development and manufacture of cables, several problems often arise in EMC compliance (FCC) for data transmission products. Further, the concentration of energy within a limited frequency range often reduces the effectiveness of receiver clock recovery and degrades product performance.

To solve some of these problems,
Various methods are used to represent the binary data transmitted on the physical medium. Some examples of the medium level coding method include Manchester split phase coding (Manchester split phase coding).
phase encoding), Manchester differential split phase encoding,
And NRZ encoding (nonreturn-to-zero encoding). An example of each of these encoding methods is shown in FIG.

[0010] The widely used Manchester encoding method (split phase) uses symmetry to eliminate changes in average (or non-evenness). In the Manchester split phase method, ones are represented by one level during the first half-bit interval and shifted to zero levels during the second half-bit interval. 0 is represented by the opposite expression. Similarly, in the split phase (differential Manchester or mark) method, except that the inversion of the phase with respect to the previous phase indicates 1 (that is, the mark) and the invariable phase indicates 0,
A similar symmetric representation is used.

Another widely used media level coding method is the nonreturn-to-zero (NRZ) representation, which reduces the bandwidth required to transmit any type of data. In the NRZ representation, a bit pulse consists of all bits
It is maintained at one of the two levels during the interval. In the NRZ (M) method, a level change is used to indicate a mark (ie, 1) and a non-level change is used to indicate 0. The NRZ (S) method uses the same method except that the level change is used to indicate a space (ie, 0). In these examples, ie, both NRZ (M) and NRZ (S), the level change (inversion) is 2
It is included in the more general classification, i.e., the example of NRZ (I), which shows the base number and the non-level changes indicate the other binary number. N
The RZ representation is efficient in terms of required bandwidth and is widely used.

However, the use of split phase (Manchester and mark) or NRZ media level representation requires additional complexity on the receiving side to determine the clock frequency.

Each of these methods described above (ie, split phase Manchester, NRZ (I), etc.) is a method of encoding a single bit of information for transmission over a physical medium. For example, in the differential Manchester split phase method, each information bit is represented by two "line bits". As shown in FIG. 1, a first information bit "a" having a value of 1 is represented by a transition from high ("1") to low ("0"), where high is the first line bit. Bit, and row is the second line bit. Similarly, the second information bit "b" having the value 1 is represented by a change from low ("0") to high ("1").

In this particular type of encoding, the line bit representing the information bit depends on the previous line bit. This is either "differential" or "inverted (i
nversion) "encoding. For example, in this example, an information bit having the value 1 is represented by two line bits having a transition from the previous state. As a result, the first information bit (" a ") Has the value 1 and when represented by a high-to-low transition, the second information bit (" b "), also having the value 1, is from the previous low-to-high line bit pair. The next information bit "c"
Also has the value 1 and is represented by a transition from the previous line bit pair from high to low. When the information bit "d" has the value 0, there is no transition from the previous line bit pair from high to low. This type of inverse or differential encoding has, inter alia, the advantage that it can be used even if the two lines of the twisted pair are inadvertently exchanged.

As described above, the differential Manchester split phase and both NRZ (I) (ie, NRZ (M) and N
The RZ (S)) media level encoding method is a differential media level method or an inverted media level method. However, NR
The Z (I) method allows for higher bandwidth transmission since only low clock cycles are required. NRZ
(I) One disadvantage of media level encoding is that it does not guarantee symmetry as in the Manchester encoding method. In addition, the receiver does not guarantee clock information to synchronize with the sender (ie, if a line bit string having the same value, such as all ones, is transmitted, the receiver's clock phase locked loop will May be off). Therefore, if NRZ (I) is used, so that evenness (parity bit polarity is balanced) is guaranteed or maximized, and clock information is provided at an opportunity, Encoding methods above the media level must be used.

In order to take advantage of the strengths of the media level coding methods, these various coding methods have been used in the past (these are, in a conceptual layered structure, the top of these media level coding methods). Positioned). For example, IB
Company M has developed an encoding method called the 8/10 encoding method. Here, 8-bit data is encoded into 10-bit words for transmission over a network (these 10-bit words are then transmitted over a network, such as NRZ (M)). It must be encoded by one of the media level encoding methods). As mentioned above, the purpose of this method is to ensure sufficient clock information while maintaining minimal non-evenness (maximum parity). However, possible 1024 (2
^{Of the 10} ) 10-bit words (mapped to 256 8-bit words), only 252 has zero non-evenness. That is, it has the same number of 1s and 0s. For example, 1
The zero bit word "1010101010" has the same number of zeros and ones and thus has a non-even parity of zero. On the other hand, a 10-bit word "1010101011" has two non-evenness because 1 is two more than zero. Thus, the "missing" of four 10-bit words (ie, 256 minus 25)
To make up for 2), the 8/10 coding method uses specific complex logic and requirements so that non-evenness is minimized. Furthermore, due to the absolute number of possible coded words, 8/10
Code and logic are extremely complex.

Another encoding method is a TAXI chip (TAXI chip) by Advanced Micro Devices (AMD).
chip) was developed as an integrated circuit. This is Advanced Mic
ro Devices TAXIchip Integrated Circuits Technical
Manual, Preliminary Rev. 1.5, 1989. This is further described in U.S. Pat. No. 4,987,572. The encoding method by AMD (hereinafter referred to as AMD encoding method) is a 4/5 code and a 5/6 code.
Define the code. For a 4/5 code, a 4-bit nibble (or simply "nibble") is received by the chip,
Encoded into a 5-bit word. Similarly, in a 5/6 code, a 5-bit word is encoded by the chip into a 6-bit word. Again, this aims to include clock information in the data stream while minimizing non-evenness.

However, according to the AMD coding method, non-evenness of 3 (that is, 4 bits of one polarity and the remaining bits of the 5 bits out of 5 bits) becomes possible, and DC balance is not maintained. This DC offset increases the jitter and affects the integrity of data transmission. For example, in 1-byte code transmission, a 40% DC offset occurs due to non-evenness.

Further, the AMD encoding method has a characteristic for synchronizing its decoding circuit on the receiving side, that is, "comma (comm)".
a) Do not provide a single 5-bit word with the "character" (a word with the "comma" characteristic means that a particular string representing that word is, for example, two words before and after in the data stream, i.e., a particular word). (The end of the first word containing the string and the beginning of the second word are not inadvertently duplicated.) Instead, in the case of AMD encoding, two words are used for the receiver to synchronize. Is defined.

[0020]

By providing an ideal balance between complexity, efficiency, function and performance,
There is a need for an encoding method that solves the above-mentioned problems.

[0021]

SUMMARY OF THE INVENTION A system and method for encoding and decoding binary data for serial transmission on a physical medium in accordance with the present invention guarantees clock information and provides no more than one non-bit per 5 bit word. A highly efficient and low complexity encoding method is provided while guaranteeing parity. The system and method of the present invention includes a 4/5 encoder in which each nibble is encoded and decoded independently of each other. The encoding system and method of the present invention provides at least one word having the "NRZ (I) comma" property, while having any magnitude less than or equal to one for any word after NRZ (I). (I) Ensure non-evenness.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The system and method of the present invention provide data transmission in a format suitable for use in high-speed serial links, such as asynchronous transfer mode (ATM) networks. The systems and methods of the present invention further provide for receiving serially transmitted formatted data and decoding the received data. In accordance with the systems and methods of the present invention, the data actually transmitted over the medium has less than one non-evenness such that the DC offset and the corresponding jitter are minimized. In addition, using the coding pattern of the present invention, at least one word is "NRZ" so that the receiver synchronizes its decoder.
(I) It has a "comma" characteristic.

FIG. 2 shows a communication network 1 including a network transmission medium 12 and network devices 14 and 16.
0 is a block diagram of FIG. Network device 16 is shown in somewhat more detail as having a receiving medium interface 18, a decoder 20, a data transceiver 22, an encoder 24, and a transmitting medium interface 26.

The receiving medium interface 18 functions to interface the circuit of the network device 16 to the network 12. Specifically, it performs functions such as receiving the transmitted bit stream, recovering the clock of the transmission unit for the receiver to synchronize with the transmitter, and transferring the received data stream and clock to the decoder 20. . Further, the reception medium interface 18
The received data from the inverse (NRZ (I)) media level encoding method is converted to NRZ format and then from serial format to 5-bit format.

Decoder 20 receives the 5-bit word from the receiving media interface (indicated by the arrow) and decodes the word to generate 4-bit nibbles and non-data bits. The 4-bit nibble and the non-data bits are transferred to the data transceiver 22.

The data transceiver 22 is a "customer" in this environment. This simply provides the binary data transmitted over the network or receives the binary data transmitted over the network, and describes how the data is transmitted or received. Do not care. In this example, the data transceiver 2
2 is configured to receive and transmit binary data in a 4-bit parallel format as well as additional non-data bits. This is used merely as an example, and other formats are possible. Further, data transceiver 22 is simply a logical representation of any unit that wishes to transmit data over network transmission medium 12 using network device 16. This is actually any communication device, which receives data in a particular format on one side and converts it to a 4-bit nibble as well as an escape format on the other side.
Reformat to For example, the data transceiver is LAN
It may be a router connected to.

Encoder 24 receives the 4-bit nibbles and non-data bits from transceiver 22 and encodes them into 5-bit words that are transmitted to transmission medium interface 26. Encoder 24 effectively performs the reverse function of decoder 20.

The transmission medium interface 26 has 5 bits
Words are received (indicated by arrows) and converted from parallel to serial and from NRZ to NRZ (I) format to provide a physical media interface through the use of a line driver or the like.

FIG. 3 shows the receiving medium interface 18 and the decoder 20 in more detail. The receiving medium interface 18 is an interface circuit (“Rx line interface circuit” 2) that conforms to the physical medium protocol used.
8 and the line receiver 30),
Receive the stream. The interface circuit converts the data stream into a format usable by the rest of the system.

The received data stream is transmitted to both the receiving clock recovery circuit 32 and the NRZ (I) -NRZ conversion circuit 34. The receiving clock recovery circuit 32 recovers the transmitting clock. A common method of clock recovery uses a phase locked loop technique. The transmitter clock is used to synchronize the rest of the recovery circuit. The NRZ (I) -NRZ conversion circuit 34
Convert NRZ (I) code to NRZ format. For example, N
In the RZ (I) inverted media level encoding method, various line transitions or line bits are converted to a standard level, for example, where the high level signal is 1 and the low level signal is 0.

The received bit clock is transferred to a deserializer 36 and a divide-by-5 circuit 42. Divide-by-5 circuit 42 divides the received bit clock by 5 to synchronize the receiver to the 5-bit word.

The converted data stream is NRZ
(I) The signal is transmitted from the -NRZ conversion circuit 34 to the serial-parallel converter 36. The data stream is input to the serial-to-parallel converter 36 in synchronization with the received bit clock. The serial-to-parallel converter 36 simply changes the received data from a serial format to a parallel format. The data in the parallel format (5-bit format) is decoded by the decoder 2.
0 and comma detector 38.

Comma detector 38 examines the bit stream in the form of a 5-bit word. The bits circulate individually through the serial-to-parallel converter 36. In the example shown, a 5-port AND gate 40 is used, where the 5-bit word is "00010". This is a 5-bit word with the NRZ (I) comma property. As mentioned above, this 5
The bit string does not appear elsewhere in the data stream and is unique to this word. A 5-bit string representing each other word in the preferred set of encoder patterns may similarly appear in a data stream where a particular 5-bit word is not transmitted. For example, the last two bits of one word, together with the first three bits of another word, may form one of the five-bit words in the encoder pattern set. This is NR
Never occurs for the Z (I) comma property word. This allows the NRZ (I) comma characteristic word to synchronize the receiver for reception of the transmitted 5-bit word. The output of the comma detector 38 is input to strobe the divide-by-5 circuit 42. The synchronized reception clock is transmitted to the decoder 20.

The decoder 20 operates in synchronization with the receiving clock.
Receives a bit word and decodes the word according to the preferred encoding pattern shown in Table 1 (the mapping below shows that these 17 code words have 16 data words as well as one non-data word "extension"). (As long as it is used to represent "(escape)", it is functionally equivalent if the codeword is redefined to map to another data nibble.)

[0035]

[Table 1]

These code words are represented by NRZ (I)
(Or another inverted or differential media level encoding method) when it has the essential transmission characteristics. This is described in more detail below in connection with the description of the encoder.

The decoder 20 comprises a ROM 44 and a logic circuit, and decodes a 5-bit code word into a 4-bit data nibble understandable by the transceiver 22. The decoded 4-bit nibbles as well as the non-data extension bits are communicated to the data transceiver 22.

Conversely, when the data transceiver 22 wants to transmit data over the network 12, the 4-bit nibbles and extension bits are transmitted to the encoder 24. The encoder 24 is shown in block diagram form in FIG.

As shown, encoder 24 receives 4-bit nibbles and extension bits from data transceiver 22. Encoder 24 encodes each of the 16 received 4-bit nibbles into a corresponding 5-bit word according to the encoding pattern shown in Table 2. This encoding pattern is realized by a look-up table in the ROM 46, for example. Further, the extension bits are encoded into a 5-bit word, so that 17 5-bit words are defined, corresponding to the corresponding 16 data nibbles and a single extension bit. Here, data nibble 13 or "110"
1 "is encoded in the NRZ (I) comma property word" 00010 ".

[0040]

[Table 2]

Table 2 further shows that each 5-bit word is NRZ
(I) shows details of the actual line signal values after being converted to a format and transmitted on a physical medium. Since the media level encoding method used is an inverse or differential encoding method, there are two possible outcomes as the actual line signal value corresponding to each 5-bit data word. Each bit of the second possible result is digitally opposite to its counterpart bit of the first possible result.

Looking carefully at the table, the non-evenness of a code word converted to NRZ (I) format is never the same in that there are always three one digital values and two other values. Never exceed one. This, besides minimizing jitter, also ensures that DC balance is maintained so as to maximize the integrity of the transmitted data. Higher transition density,
That is, there are an average of 3.1 transitions for five signal elements. The run-length of any set of 1s or 0s without further interruption never exceeds 5. This allows easy synchronization of the receiving units. Finally, N
One of the code words after RZ (I) conversion ("00010")
Have NRZ (I) comma characteristics (characteristics for synchronizing with a break). This is because this bit sequence never occurs as any part of any combination of other code words. NRZ
(I) The comma property allows the receiver to get immediate code word synchronization with a simple 5-bit pattern match (indicated by the comma detector 38) each time this word is used. To Upon conversion to the NRZ (I) format, the code words of the preferred code set having NRZ (I) non-evenness equal to 1 are:
It is considered to have one "NRZ (I) non-evenness". Also, when converted to NRZ (I) format, code words of the preferred code set having a comma property are considered by the present invention to have "NRZ (I) comma property" (shown in FIG. 1). As such, the NRZ (I) format is either a mark or a space).

The preferred encoding method is conventionally, in particular, LA
It was designed to provide octet (8 bit byte) transmissions that occur in the environment of N transmission subsystems. For example, a data nibble followed by an extended nibble is
Shows one of the 16 command symbols. The command sequence is then identified by each of the 16 nibbles required in each protocol. Further, the two extended nibbles in the sequence have special meaning, such as representing a null symbol that supports a system that requires an idle symbol.
Finally, octet framing is achieved by providing a provision to place all extension symbols immediately after the completed octet. This allows the receiving side to easily establish an octet boundary.

The output (5 bits) of the encoder 24 is transmitted to the transmission medium interface 26. The parallel data words are converted to serial form by a serializer 48. Parallel-to-serial converter 48 simply converts the 5-bit word into a serial format. The serial data stream is transmitted from the parallel-to-serial converter 48 to the NRZ-NRZ (I) conversion circuit 50 in synchronization with the transmitting clock (five times the frequency of the nibble clock for inputting data to the parallel-to-serial converter 48). Is output. NRZ-NRZ (I) conversion circuit 5
0 converts the data stream in NRZ format to NRZ (I) format for transmission over network 12.
The line driver 52 and the Tx line interface circuit 54 have data values and output impedances appropriate for the actual physical interface.
Prepare the stream.

In summary, the following is disclosed regarding the configuration of the present invention.

(1) A method of converting a predetermined code set at the time of transmission, wherein the code set is grouped into n-bit groups, and each of the n-bit groups corresponds to n + a bits. Converting into groups, each group of n + a bits is selected from 2 ^{n + a} options and its NRZ
(I) the conversion step, wherein the non-evenness is a group having a property of being equal to or less than a predetermined value m, and at least one selected group of n + a bits has an NRZ (I) comma property for synchronization; A method that includes (2) A method of converting a predetermined code set upon reception, comprising the step of receiving the predetermined code set of n + a bit groups, wherein each group of n + a bits has 2 ^{n + a} bits Selected from the options,
A group having a characteristic that the NRZ (I) non-evenness is equal to or less than a predetermined value m, wherein at least one selected group of n + a bits includes NRZ (I) for synchronization.
A method comprising the steps of receiving, having a comma characteristic, and converting each group of n + a bits into a corresponding group of n bits. (3) The method according to claim 1 or 2, wherein n is equal to the integer 4, a is equal to the integer 1, and m is equal to the integer 1. (4) A system for converting a predetermined code set upon transmission, wherein the code set is grouped into groups of n bits, and each group of n bits is converted into a corresponding group of n + a bits. Means, wherein each group of n + a bits is a group selected from 2 ^{n + a} options and whose NRZ (I) non-evenness is less than or equal to a predetermined value m;
the conversion means, wherein at least one selected group of a bits has NRZ (I) comma characteristics for synchronization. (5) The system according to (4), wherein said converting means includes means for formatting said selected group of n + a bits into an NRZ inverted (NRZ (I)) medium level encoding method format. (6) The system according to (4), wherein said predetermined code set has non-data bits, and said system includes means for converting said non-data bits into a corresponding group of n + a bits. (7) A system for converting a predetermined code set upon reception, wherein the system receives the predetermined code set of n + a bit groups, wherein each group of n + a bits has 2 ^{n + a} bits. Selected from the options,
A group having a characteristic that the NRZ (I) non-evenness is equal to or less than a predetermined value m, wherein at least one selected group of n + a bits includes NRZ (I) for synchronization.
A system comprising: said receiving means having a comma characteristic; and means for converting each group of n + a bits into a corresponding group of n bits. (8) The system according to (7), wherein said converting means includes means for formatting said selected group of n + a bits from an NRZ inverted (NRZ (I)) medium level encoding method format to an NRZ format. (9) A system for transmitting a predetermined code set from a first network device to a second network device via a network transmission medium, wherein the system includes the first network device.
A) said first network device grouping said first code set into n-bit groups; and each said n-bit group. Into a corresponding group of n + a bits to generate a second code set, wherein each group of n + a bits is 2 ^{n + a}
And a NRZ (I) non-parallelism of which is less than or equal to a predetermined value m, wherein at least one selected group of n + a bits includes:
Comprising means for synchronizing with NRZ (I) comma characteristics, and means for transmitting the second set of codes over the network transmission medium; b) the second network device comprises: The transmitted n
Means for receiving a second code set of a group of + a bits, and means for converting the second code set to the first code set, each group of n + a bits corresponding to n bits. And a conversion means for converting the data into a group. (10) The above (9), wherein the converting means of the first network device includes means for formatting the selected group of n + a bits into an NRZ inverted (NRZ (I)) medium level encoding method format. System. (11) The system according to (4), (7) or (9), wherein n is equal to an integer 4. (12) The system according to (4), (7) or (9), wherein a is equal to the integer 1. (13) The system according to (4), (7) or (9), wherein m is equal to the integer 1. (14) n is equal to the integer 4, a is equal to the integer 1, m is equal to the integer 1, and the selected group of n + a bits is 11
111, 10111, 11101, 10101, 11010, 10010, 11001, 110
11, 01110, 00111, 01101, 01111, 01010, (00010),
(5) comprising the group of 01001, 01011, 11110, wherein (00010) has the NRZ (I) comma property described above;
The system according to (8) or (10).

[0047]

The method and system of the present invention provides high quality binary data in serial transmission over physical media while ensuring clock information and NRZ (I) non-evenness of less than one per 5 bit word. It will be appreciated that encoding and decoding is efficient and low complexity. The 4/5 encoder encodes and decodes each nibble independently of each other, while "N
Guarantees NRZ (I) non-evenness with a magnitude less than or equal to 1 for any word after NRZ (I), while providing at least one word with the "RZ (I) comma" property. Thus, according to the present invention, there is provided an encoding method that solves the problems associated with conventional encoding techniques by providing an ideal balance between complexity, efficiency, function and performance.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a binary data representation according to a conventional medium level encoding method.

FIG. 2 is a diagram illustrating a network including a network device using the encoding system and method of the present invention.

FIG. 3 is a block diagram showing one embodiment of an encoder and a transmission medium interface of the present invention.

FIG. 4 is a block diagram showing one embodiment of a decoder and a receiving medium interface of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Communication network 12 Network transmission medium 13 Data nibble 14 and 16 Network device 18 Reception medium interface 20 Decoder 22 Data transceiver 24 Encoder 26 Transmission medium interface 28 Rx line interface circuit 30 Line receiver 32 Receiver clock recovery circuit 34 NRZ (I) -NRZ conversion circuit 36 Serial-parallel converter 38 Comma detector 40 5-port AND gate 42 5 division circuit 44, 46 ROM 48 Parallel-serial converter 50 NRZ-NRZ (I) conversion circuit 52 Line driver 54 Tx line interface circuit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H03M 5/06 H03M 7/14 H04L 25/49

Claims (13)

(57) [Claims] 1. A method for converting a predetermined code set upon transmission, the method comprising: grouping the code sets into n-bit groups; each n-bit group being a corresponding group of n + a bits. Where each group of n + a bits is a group selected from 2 ^{n + a} options and whose NRZ (I) non-evenness is less than or equal to 1 , and wherein at least n + a bits The above conversion step, wherein one selected group has an NRZ (I) comma property for synchronization. 2. A method for converting a predetermined code set upon reception, comprising the step of receiving said predetermined code set of n + a bit groups, wherein each group of n + a bits is 2 ^{n + a} NRZ
(I) a group having a property that non-evenness is 1 or less , wherein at least one selected group of n + a bits has an NRZ (I) comma property for synchronization; Converting each group of n into a corresponding group of n bits. 3. n is an integer 4, a is an integer 1, and so on.
Correct, Method according to claim 1 or 2. 4. A system for converting a predetermined code set upon transmission, comprising: means for grouping said code set into n-bit groups; each said n-bit group to a corresponding group of n + a bits. Means for converting, wherein each group of n + a bits is a group selected from 2 ^{n + a} options and whose NRZ (I) non-evenness is 1 or less , wherein at least 1 of n + a bits The conversion means, wherein the two selected groups have NRZ (I) comma characteristics for synchronization. 5. The apparatus of claim 5, wherein the converting means comprises means for formatting the selected group of n + a bits into an NRZ inverted (NRZ (I)) medium level encoding method format.
The system according to claim 4. 6. The method of claim 1, wherein the predetermined code set has non-data bits, and the system sets the non-data bits to n
+ A bit means for converting to a corresponding group,
The system according to claim 4. 7. A system for converting upon receipt of a predetermined code set, said means for receiving said predetermined code set of groups of n + a bits, wherein each group of n + a bits comprises:
NRZ (I) selected from 2 ^{n + a} options
A group having a property that non-evenness is 1 or less , wherein at least one selected group of n + a bits includes:
A system comprising: said receiving means having NRZ (I) comma characteristics for synchronization; and means for converting each group of n + a bits into a corresponding group of n bits. 8. The system of claim 7, wherein said converting means includes means for formatting said selected group of n + a bits from an NRZ inverted (NRZ (I)) medium level encoding method format to an NRZ format. 9. A system for transmitting a predetermined code set from a first network device to a second network device via a network transmission medium, the system comprising the first network device and the second network device. A) the first network device comprises: means for grouping the first code set into n-bit groups; and each of the n-bit groups into a corresponding group of n + a bits. Means for converting to generate a second code set, wherein each group of n + a bits is selected from 2 ^{n + a} options, and whose NRZ (I) non-evenness is
A means having at least one selected group of n + a bits having a NRZ (I) comma property for synchronization, the group having a characteristic being less than or equal to 1 and the network transmission of the second code set. Means for transmitting over a medium; b) means for receiving the transmitted second code set of the group of n + a bits; b) the second network device; Means for converting to said first code set, said converting means for converting each group of n + a bits to a corresponding group of n bits. 10. The method of claim 9, wherein said converting means of said first network device includes means for formatting said selected group of n + a bits into an NRZ inverted (NRZ (I)) medium level encoding method format. The described system. 11. The system according to claim 4, 7 or 9, wherein n is equal to the integer 4. 12. A system according to claim 4, wherein a is equal to the integer 1. 13. n is an integer 4 and a is an integer 1.
Properly, the selected group of n + a bit, 11111,101
11, 11101, 10101, 11010, 10010, 11001, 11011, 0111
0,00111,01101,01111,01010, (00010), 01001,0
1011 and 11110, and (00010) is the above N
11. The RZ (I) comma property.
The described system.